Solid-State Transformer for Energy Efficiency Enhancement DOI: http://dx.doi.org/10.5772/intechopen.84345

t ¼ 0:17 s, the load increases its demand; that means, there is more power consumption by the load, and this causes the grid to start delivering power to the load. The simulation continues in such a way that the distributed generation is switched

It is possible to deploy a communication system that could satisfy the communication requirements and provide an enhanced operational capability in an SST

> NB-PLC: �150 km or more

BB-PLC: �1.5 km NB-PLC:

(AMI) NAN/FAN WAN

BB-PLC: Small-scale AMI

NAN/FAN AMI (with FTTH

HAN

AMI NAN/FAN

AON: �10 km WAN

BPON, GPON: �20–60 km EPON: �10–20 km

ADSL: �4 km ADSL2: �7 km ADSL2+: �7 km

VDSL: �1.2 km VDSL2: �300 m (maximum rate)–1 km (50 Mbps)

Large-scale automatic metering infrastructure

Technology Data range Range Use in smart grid

1–10 Kbps (low data rate PHYs) 10–500 Kbps (high data rate PHYs)

�200 Mbps (short

155–622 Mbps (up/

1.244–2.448 Gbps (down). EPON: 1 Gbps up/ (down)

8 Mbps (down) and 1.3 Mbps (up) ADSL2: 12 Mbps (down) and up to 3.5 Mbps

52–85 Mbps (down and 16–85 Mbps

VDSL2: up to 200 Mbps (down/up)

systems) Passive optical

NB-PLC:

BB-PLC: 1–10 Mbps (long range)

range)

AON: 100 Mbps (up/ down)

PON BPON

down) GPON: 155–2448 Mbps

(up)

(up). ADSL2+: 24 Mbps (down) and up to 3.3 Mbps

(up)

(up)

ADSL ADSL:

VDSL VDSL:

off and instead the storage energy starts operating.

4. Communication requirements

Research Trends and Challenges in Smart Grids

Narrowband PLC (NB-PLC)

Broadband PLC (BB-PLC)

Active optical networks (AON)

networks (PON): BPON, -EPON GPON

Power line communication (PLC)

Optical communications

Digital subscriber line (DSL)

Table 10.

134

Wired technologies for SG.

network. Several types of topologies can be considered depending on the application. For instance, in a star-type topology, the communication linkage is established between each SSTs and the control center directly. Other topologies allow improved connectivity with alternate connections and meshed links. However, in all cases, a certain level of security, scalability, and minor delay in the information and bi-directional data transfer capabilities is required. While information capability performs digital monitoring of SST variables (as in SCADA systems), the bi-directional data transfer capability allows fast responses to disturbances such that system's performance can be improved accordingly [27]. In fact, the smart grid (SG) concept is based on reliable real-time data availability and utilization for more intelligent decision-making.

There could be two forms of communication in SST networks: wired or wireless. Their selection depends on the bandwidth and the cost of the telecommunications infrastructure [28]. In the wired case, there are technologies based on power line communications (PLC) and optical communications and digital subscriber line (DSL) [29]. Table 10 shows the comparison of wired communication technologies for smart grids according to coverage range and maximum theoretical data transmission. It is observed that optical fiber main application is the connectivity between transmission/distribution substations, thus, forming large coverage areas satisfying very high volumes of data and low latency. However, the main disadvantage is its high installation and equipment costs. On the other hand, PLC and DSL are technologies that can be merged on existing copper-wired networks, but their bigger limitations are scalability and network flexibility [30].

In the case where the installation is above ground level, SSTs could have a wireless communication system. In fact, whenever possible, wireless technologies are preferred due to its flexibility and low cost; they can cover difficult access areas (distant or inaccessible) in power system monitoring applications [31]. As an example, a multipoint to point (MP2P) communication system for SST-based power system is shown in Figure 17. There are several wireless technologies that depend on the coverage and data rate, and these technologies allow the adoption of the multilayer architecture for smart grid as shown in Table 10. In the case of an SST-control center communication network, it is also possible to incorporate different intelligent electronic devices (IEDs), remote terminal units (RTU), substation automation solutions (SAS), universal gateways, smart meters, etc. There will be an increased complexity in the network operation due to the large amounts of data. Hence, these types of applications will require higher reliabilities and lower latencies.

Figure 17. Communication network for SST.

There are several wireless technologies that depend on the coverage and data rate, and these technologies allow the adoption of the multilayer architecture for smart grid as shown in Table 10. In the case of an SST-control center communication network, it is also possible to incorporate different intelligent electronic devices (IEDs), remote terminal units (RTU), substation automation solutions (SAS), universal gateways, smart meters, etc. There will be an increased complexity in the network operation due to the large amounts of data. Hence, these types of applications will require higher reliabilities and lower latencies. For such complex networks, a geographical-dependent structure is required.

According to the geographical service, networks are classified in home area network (HAN), neighborhood area networks (NANs), and wide area network (WAN). These networks have different coverage areas as detailed in Figure 18. HAN refers to networks within a single point facility (e.g., substation); it can range from a single home to a business area network (BAN) or industrial area network (IAN). Outside the single point facility, there are NANs and WANs. NAN, also known as field area network (FAN), connects several HANS and covers the transmission or distribution areas within several square kilometers. On the other hand, WAN connects several NANs, and it is considered the backbone of the communication system. It can cover thousands of square kilometers including the main control center. WAN can be a hybrid network with a mixture of wired and wireless sections [32].

For applications that could be deployed wirelessly, the reader can find an updated selection of available technologies including satellite and mobile communications in Table 11. The communication spectrum could present congestion in

licensed and unlicensed bandwidths due to the increasing number of technologies sharing the same resource. Therefore, the network designer must consider more stringent security mechanisms. A more efficient spectrum can deliver increased

Technology Data rate Range Use in

256 Kbps Between 10 and 75 m

> IEEE 802.11e/s/n: 300 m (outdoors)

IEEE 802.11p: 1 km IEEE 802.11ah: 1 km IEEE 802.11af: >1 km

IEEE 802.16: 0–10 km

IEEE 802.16 m: 0–5 km (optimum) 5–30 km (acceptable) 30–100 (reduced performance) km

HSPA+: 0–5 km V2G

LTE-Advanced: 0–5 km (optimum) 5–30 km (acceptable) 30–100 km (reduced performance)

Depend on number of satellites and their beams

IEEE 802.11e/s: 54 Mbps

IEEE 802.11 n: 600 Mbps

IEEE 802.11af: 26.7 Mbps

IEEE 802.11ah: 40 Mbps

IEEE802.16: 128 Mbps down and 28 Mbps up

100 Mbps for mobile users, 1 Gbps for fixed users

and 5.75 Mbps up

and 86 Mbps up

500 Mbps up

2.4–28 Kbps Inmarsat-B: 9.6 up to 128 Kbps

BGAN: 384 up to 450 Kbps

WAN HSPA+ 84 Mbps down and 22 Mbps up

WAN IEEE802.16 m

WPAN IEEE 802.15

Wi-Fi IEEE802.11e (QoS-

enhancements)

Solid-State Transformer for Energy Efficiency Enhancement

DOI: http://dx.doi.org/10.5772/intechopen.84345

IEEE802.11 s (mesh networking)

(fixed and mobile broadband wireless access)

Satellite LEO Iridium:

(advanced air interface)

IEEE802.11p wireless access in vehicular environments

IEEE 802.16j (multi-hop relay) IEEE802.16 m:

HSPA 14.4 Mbps down

LTE 326 Mbps down

LTE-advanced 1 Gbps down and

IEEE802.11n (ultrahigh network throughput)

(WAVE)

WiMAX IEEE 802.16

Cellular communications

Cellular communications

3G

4G

Table 11.

137

Wireless technologies for SG.

smart grid

Vehicleto-grid (V2G) HAN: AMI

V2G HAN AMI

AMI NAN/FAN WAN

AMI NAN/FAN

HAN: AMI NAN

WAN AMI

Figure 18. Communication layer for SST.

